Optical analytical instruments are known to the prior art. Typically such instruments include a source of analytical radiation, a detector for the radiation, a system for supporting a sample to be analyzed and optical elements for directing the radiation along an optical path of the instrument. The present invention relates to an improved beam condenser system for such an instrument.
In the prior art, beam condensers are often employed to improve the sensitivity of the instrument. For example, the available sources of some desired analytical radiation have practical limits as to their power. An example of such an analytical radiation limitation within an analytical instrument is found in the context of an infrared spectrometer employing an interferometer within its operating system. Since there is a practical limit to the intensity of infrared sources, it has become the practice to condense the analytical beam at the sample, thereby concentrating it and improving the signal to noise ratio. However, in the prior art, this has required tedious and time-consuming alignment and realignment of the condenser optical elements as a result of the many interactive alignments that are necessary. Even a highly skilled and experienced operator has difficulty duplicating the theoretical "throughput" when such systems are employed.
In addition to concentrations of the analytical radiation, other applications wherein beam condenser systems have advantage are in the analysis of small samples, the use of attenuated total reflectance (ATR) crystals for the study of surface effects and in the mapping or profiling of a sample, particularly an inhomogeneous sample. Beam condenser systems employed in the prior art for these purposes have the deficiencies noted above.